The invention relates to the construction and use of an axially contractable and expandable piston and cylinder assembly.
Such assemblies as heretofore developed and as heretofore used, for instance in slot presses for construction work, have the decided disadvantage, especially if they are of the so-called short stroke type, that the axial shift of the piston within the cylinder to precisely parallel positions cannot always be assured. Due to the axially relatively small contact areas between the piston and the cylinder, the piston is apt to become cocked and thereby cause various difficulties the worst of which is the jamming of the piston within the cylinder.